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Compute the spatial Laplacian matrix of a coordinate matrix

Source: R/spatial_weights.R
spatial_laplacian.Rd

This function computes the spatial Laplacian matrix of a given coordinate matrix using specified parameters.

Usage

spatial_laplacian(
  coord_mat,
  dthresh = 1.42,
  nnk = 27,
  weight_mode = c("binary", "heat"),
  sigma = dthresh/2,
  normalized = TRUE,
  stochastic = FALSE,
  handle_isolates = c("self_loop", "keep_zero", "drop")
)

Arguments

coord_mat

A numeric matrix representing coordinates

dthresh

Numeric, the distance threshold for adjacency (default is 1.42)

nnk

Integer, the number of nearest neighbors for adjacency (default is 27)

weight_mode

Character, the mode for computing weights, either "binary" or "heat" (default is "binary")

sigma

Numeric, the sigma parameter for the heat kernel (default is dthresh/2)

normalized

Logical, whether the adjacency matrix should be normalized (default is TRUE)

stochastic

Logical, whether the adjacency matrix should be stochastic (default is FALSE)

handle_isolates

How to treat zero-degree nodes when normalizing: "self_loop" (default), "keep_zero", or "drop".

Value

A sparse symmetric matrix representing the computed spatial Laplacian

Examples

coord_mat <- matrix(c(1, 2, 3, 4, 5, 6), nrow = 3, ncol = 2)

result <- spatial_laplacian(coord_mat, dthresh = 1.42, nnk = 27, weight_mode = "binary")